The present invention relates to a method of manufacturing a bag-like rubber weir main body. The bag-like body inflates by the in-flow of water to block a river thereby forming an inflated weir, and which deflates by the discharge of water thereby allowing free the flow of water in the river.
For a rubber weir of increased size, large sized equipment is required to manufacture a rubber weir main body resulting in the increased cost of equipment. Further, at a job site, for example in the interior of a mountainous region, the transport of rubber weir main bodies is difficult to carry out.
To cope with the above-described problem, there has been conventionally proposed a method of manufacturing a main body by previously forming main body segments by means of dividing a rubber weir main body in the circumferential direction, and joining these main body segments. This prior art (Examined Japanese Patent Publication HEI 3-35098) will be described with reference to FIG. 8.
Namely, a rubber weir main body is manufactured by forming a material removed portion with stepped portions at edges of rubber weir main body segments 01 previously vulcanized and molded; fitting a rubber sheet 02 containing a reinforcing material, which is previously vulcanized and molded so as to be matched to the shape of the material removed portion, in the material removed portion of the rubber weir main body segments through an unvulcanized rubber 03; bonding then vulcanizing and bonding them.
This method, however, must prepare the previously vulcanized rubber sheet 02 containing a reinforcing material, to thereby increase the number of process steps and the cost of the device.
Further, when the materials of the edges of the rubber weir main body segments 01 are not accurately removed, the previously vulcanized rubber sheet 02 is not fitted with high accuracy even in the presence of the unvulcanized rubber therebetween, and thereby gaps 04 are possibly formed. Additionally, when the amount of the unvulcanized rubber 03 is unsatisfactory to be adjusted, gaps 04 are also generated, which causes separation and breaking.
Moreover, the rubber weir main body segments 01 are vulcanized and bonded to each other through the previously vulcanized rubber sheet 02 containing a reinforcing material; however, at this time the rubber sheet 02 is vulcanized gain, so that it is excessively vulcanized and is made rigid in its physical property. As a consequence, a flat plate portion with high rigidity is formed only in the joint portion, and accordingly the rubber weir main body is difficult to form into smooth curved shape when being raised.
Taking the above circumstances into consideration, the present invention has been made, and an object of the present invention is to provide a method of manufacturing a rubber weir main body capable of reducing a part of the conventional manufacturing processes, and accurately bonding rubber weir main body segments without enlarging the size of equipment.
To achieve the above object, according to the present invention, there is provided a method of manufacturing a rubber weir main body, which manufactures a rubber weir main body intended to rise by the in-flow of a fluid and to fall by the discharge of the fluid by integrally bonding at least two main body segments divided in the circumferential direction to each other, including the steps of: forming a material removed portion with stepped portions at edges of the rubber weir main body segments previously manufactured; abutting the rubber weir main body segments on each other at the edges; laminating unvulcanized rubber sheets containing reinforcing canvasses and an unvulcanized rubber sheet on the material removed portion formed between both of the rubber weir main body segments contacted with each other; and integrally vulcanizing and bonding them.
By use of the unvulcanized rubber sheets containing reinforcing canvasses, it is possible to reduce the number of processes. Further, when the material removed portion of the rubber weir main body segments is not accurately formed, since the unvulcanized rubber sheets containing reinforcing canvasses are matched to material removed portion, it is possible to bury gaps and hence to prevent the separation and breaking.
Since the rubber weir main body segments are joined and vulcanized/bonded to each other using the unvulcanized rubber sheets, it is possible to prevent the generation of any excessively vulcanized portion, and hence to manufacture the rubber weir main body being substantially homogeneous as a whole.